The present invention is concerned with a reaming and counterboring cutting tool bit intended to be driven in rotation for the purpose of removing a preexisting weld between a tube (e.g., a steam tube) that has been inserted into a bore in the side wall of a header (fluid distributor) and the side wall of the bore, while at the same time refacing a reference surface or seat on the interior wall of the header around the bore to permit automatic welding equipment to be precisely located relative to the refinished tube end within the bore. This permits the tube end to be rewelded to the bore side wall from within the header in a well-known manner using automatic electric arc welders.